USMC Small Wars Manual (1940, reprinted 1990).
A clean, bright text. Unlike the others found on the internet, this one allows you, in your pdf s/w, to reset your startup choices (page, zoom, etc.). It is also full-text searchable. 1990 USMC reprint of an "historical text." "...can help Marines prepare for low-intensity conflicts which in the 1930's were referred to as small wars." See http://en.wikipedia.org/wiki/Small_Wars_Manual